Impact Effects
Robert Marcus, H. Jay Melosh, and Gareth Collins

Your Inputs:
Distance from Impact: 1000.00 km = 621.00 miles
Projectile Diameter: 1818.55 m = 5964.86 ft = 1.13 miles
Projectile Density: 38 kg/m3
Impact Velocity: 222000.00 km/s = 137862.00 miles/s
Impact Angle: 30 degrees
Target Density: 1000 kg/m3
Target Type: Competent Rock or saturated soil

Energy:
2.95 x 1027 Joules = 7.04 x 1011 MegaTons TNT
The average interval between impacts of this size somewhere on Earth is 1.5 x 1011years

Crater Size:
What does this mean?


Transient Crater Diameter: 307.69 km = 191.08 miles
Final Crater Diameter: 651.76 km = 404.74 miles

The crater formed is a complex crater.

Thermal Radiation:
What does this mean?


Time for maximum radiation: 0.01 seconds after impact

Visible fireball radius: 2789.6 km = 1732.4 miles
The fireball appears 634.0 times larger than the sun
Thermal Exposure: 1.36 x 1011 Joules/m2
Duration of Irradiation: 3727 seconds
Radiant flux (relative to the sun): 36462.8

Effects of Thermal Radiation:


Clothing ignites

Much of the body suffers third degree burns

Newspaper ignites

Plywood flames

Deciduous trees ignite

Grass ignites


Seismic Effects:
What does this mean?


The major seismic shaking will arrive at approximately 200.0 seconds.
Richter Scale Magnitude: 12.5 (This is greater than any earthquake in recorded history)
Mercalli Scale Intensity at a distance of 1000 km:

IX. General panic. Masonry D destroyed; masonry C heavily damaged, sometimes with complete collapse; masonry B seriously damaged. (General damage to foundations) Frame structures, if not bolted, shifted off foundations. Frames racked. Serious damage to reservoirs. Underground pipes broken. Conspicuous cracks in ground. In alluviated areas sand and mud ejected, earthquake fountains, sand craters.

X. Most masonry and frame structures destroyed with their foundations. Some well-built wooden structures and bridges destroyed. Serious damage to dams, dikes, embankments. Large landslides. Water thrown on banks of canals, rivers, lakes, etc. Sand and mud shifted horizontally on beaches and flat land. Rails bent slightly.

Masonry B. Good workmanship and mortar; reinforced, but not designed in detail to resist lateral forces.
Masonry C. Ordinary workmanship and mortar; no extreme weaknesses like failing to tie in at corners, but neither reinforced nor designed against horizontal forces.
Masonry D. Weak materials, such as adobe; poor mortar; low standards of workmanship; weak horizontally.


Ejecta:
What does this mean?


The ejecta will arrive approximately 494.4 seconds after the impact.
Average Ejecta Thickness: 93.4 m = 306.32 ft
Mean Fragment Diameter: 1.0 cm = 0.41 inches


Air Blast:
What does this mean?


The air blast will arrive at approximately 3333.3 seconds.
Peak Overpressure: 25503062.5 Pa = 255.0306 bars = 3621.4349 psi
Max wind velocity: 3687.8 m/s = 8249.5 mph
Sound Intensity: 148 dB (Dangerously Loud)
Damage Description:


Multistory wall-bearing buildings will collapse.

Wood frame buildings will almost completely collapse.

Multistory steel-framed office-type buildings will suffer extreme frame distortion, incipient collapse.

Highway truss bridges will collapse.

Highway girder bridges will collapse.

Glass windows will shatter.

Cars and trucks will be largely displaced and grossly distorted and will require rebuilding before use.

Up to 90 percent of trees blown down; remainder stripped of branches and leaves.



Tell me more...

Click here for a pdf document that details the observations, assumptions, and equations upon which this program is based. It describes our approach to quantifying the important impact processes that might affect the people, buildings, and landscape in the vicinity of an impact event and discusses the uncertainty in our predictions. The processes included are: atmospheric entry, impact crater formation, fireball expansion and thermal radiation, ejecta deposition, seismic shaking, and the propogation of the atmospheric blast wave.



Earth Impact Effects Program Copyright 2004, Robert Marcus, H.J. Melosh, and G.S. Collins
These results come with ABSOLUTELY NO WARRANTY

Originally posted by akewlkid
SO I researched the pictures and found that there is indeed a gap of like 20 hours, but why the question of video editing and tampering as previously mentioned? The comet just looks to be further along than before.

I tried to post the pics, but couldn't do it, so here're the links for you

The list -- sohowww.nascom.nasa.gov... (Note the gap between 20040417_0454 and 20040417_2354)

The pics --

sohowww.nascom.nasa.gov...

sohowww.nascom.nasa.gov...